As you mentioned WordPress is offered by Apache which is run by user daemon. Therefore, when it creates a folder or file it will create it using daemon:daemon as user:group and that's a problem since the rest of the files have the ownership bitnami:daemon in order to make it easier for the developer to modify the application when he connects via SSH/SFTP with the user bitnami.

I would not change the permissions configuration in the WP folder since that can give you more problems, therefore I see two solutions in this moment:

A) Set a CronJob which recofigures the permissions to bitnami:daemon to the uploads folder every minute (or every 10 minutes).

B) Add the user bitnami to the group daemon. I would try to avoid this options since you have to modify the system users' configuration.

Let’s see how we can add new and existing users to primary and secondary groups in Linux. The standard Linux permission model makes use of users, groups, and file permissions (i.e., read, write, execute, and a sticky bit). Adding a User to a Group in...